1. Field
Apparatuses and methods consistent with exemplary embodiments relate to measuring a pulse wave that carries biological information.
2. Description of the Related Art
In a commonly used pulse transit time (PTT) measuring method, PTT is obtained by measuring an electrocardiogram signal and comparing the measured electrocardiogram signal with a pulse wave measured at an extremity of a body, such as a hand or a foot which is the farthest point from the heart. When the electrocardiogram signal is used, a potential difference must be measured through an electrical path including the heart, and therefore a device must be in contact with both hands or a patch must be attached to the chest.
In a method of measuring the pulse wave without measuring the electrocardiogram signal, pulse waves are measured at two points of the extremity of the body and a time difference between a pulse wave signal at the point closer to the heart and a pulse wave signal at the point closer to the end of the body is measured. At this time, the smaller a distance between the two points at which the pulse wave signals are sensed, the smaller the time difference between the two pulse wave signals. Therefore, the smaller the distance between the two points at which the pulse wave signals are sensed, the higher a sampling frequency required for measuring the pulse wave signals.